The subject matter disclosed herein relates to a system and method for blood pressure measurement. More specifically, the subject matter disclosed herein relates to a system and method for a non-invasive blood pressure measurement that is configured to more accurately and more rapidly estimate one or more blood pressure parameters.
The knowledge of a patient's blood pressure is of great value to those engaged in diagnosis, prognosis and treatment of disease states. In particular, the determination of arterial blood pressure is an essential element in the diagnosis of a patient suspected of having cardiovascular disease. Normal human arterial blood pressure cyclically varies between 80 and 120 mmHg due to the heart beating and moving blood through the vasculature, whereas, for example, elevations of the arterial blood pressure above the specified range, which is known as hypertension, is likely to be found in cases of congestive heart failure.
Non-invasive blood pressure (NIBP) monitors typically inflate a blood pressure cuff, which is wrapped around the upper arm of the patient to a pressure level above the patient's systolic pressure and measure very small amplitude pressure oscillations within the cuff as the cuff is deflated either in steps or continuously. The pressure oscillations in the cuff are due to volume changes resulting from the heart beating and pumping the blood through the arterial system. The amplitude of the cuff pressure oscillations changes as the cuff pressure itself changes. The data set, which describes the cuff oscillation amplitude as a function of the cuff pressure, is commonly known as an oscillometric envelope. The oscillometric envelope obtained from the cuff pressure data is used to determine the patient's blood pressure. The cuff pressure corresponding to the maximum oscillation amplitude is typically taken as the mean arterial pressure (MAP). Systolic and diastolic pressures are computed by finding the cuff pressure levels at which a fixed ratio of the maximum oscillation amplitude occurs. Some NIBP monitors also use details in the shape of the oscillometric envelope to compute the systolic and diastolic pressures.
The cuff pressure data can, in some cases, contain various types of artifacts that may hinder the ability of the NIBP monitor to estimate the blood pressure parameters accurately. Two primary classes of artifacts are patient motion and transient baseline effects. Conventional NIBP techniques are often not capable of handling these artifact problems effectively and this can introduce imprecision into the blood pressure estimates, and may also result in longer determination times, which can be uncomfortable to the patient. Transient baseline effects are well known to those skilled in the art, and may include such phenomena as the heating and cooling of the air within the cuff, the visco-elastic effects of the cuff material which influence the time needed to reach pressure-volume equilibrium, and physiological changes in fluid and tissue volume under the cuff.
Hence there exists a need for providing a method of measuring blood pressure, which enhances the speed of an NIBP monitor without sacrificing accuracy of blood pressure measurement.